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For some people, it's chocolate. For others, pizza. Or perhaps it's Chinese food, cheeseburgers or fries.

Most people experience food cravings of some type. But where do those cravings come from? And what, if anything, can be done to control them?

Cravings are nothing more than a desire for something that's rewarding, said Dr. Rajita Sinha, a professor of psychiatry and neuroscience at Yale University School of Medicine in New Haven, Connecticut.

"Different things can trigger them – smells or visual cues, for example," she said. "In the case of food, our sensory systems trigger the motivational or reward pathways in the brain. You don't need to see the food per se, but people, places and things that remind you of a food that's rewarding will do it. That motivational signal will fire up our brains."

Research has shown that can increase heart rate, gastric activity and salivation, as well as a pattern of responses in several pathways in the brain associated with reward. Food stimulation to activate glucose metabolism, the process needed to turn food into energy, and the release of dopamine, the brain chemical involved in motivating us toward rewarding and feel-good things.

Cravings are not the same as hunger and can occur without stimuli, such as when people have deprived themselves of a food their brain identifies as rewarding and they can't stop thinking about it.

These reward pathways are connected to the decision-making regions in our brain, Sinha said. "A part of the brain behind the forehead adds the concept of value. You smell a chocolate cake and think, 'Mmmm, this is of high value because it will taste good and be rewarding.' Reward is a powerful signal."

There's an evolutionary reason for that, said Dr. Meghan Butryn, a professor and associate department head in the department of psychological and brain sciences at Drexel University in Philadelphia.

"Our brains evolved during a long period of human history when access to food was unreliable and often scarce," Butryn said. "We were very motivated to seek out food high in calories, and when we did have access to this food we'd want to eat quite a lot of it. We found it rewarding to eat this food because it helped us to survive.

"All of that brain circuitry that creates that feeling of reward when we eat still exists even though the environment we live in has changed," she said. "Now, in most developed countries there is an abundance of access to food, and we do little work to obtain it."

Eating patterns, however, become habitual, or automatic, along with the associations between foods and the rewards they bring, she said.

"Any time you engage in a behavior, the response you get shapes the likelihood you will engage in that behavior again," Butryn said. "When you eat sodium, added sugar and saturated fat, there is a high reward response that shapes our behavior and makes us want to engage with it again."

But that doesn't mean those feelings can't be overcome. It just takes effort, Sinha and Butryn said.

One way to overcome cravings is through distraction, Sinha said. "You can take your mind off of it, tell yourself you need to work, you have other things to do."

Another strategy is to embrace the feeling but not follow up with action, a process called urge surfing, she said. "That is a very nice way of saying just sit with it in a mindful way. Notice the urge and acknowledge it. If you sit with an urge but don't do anything about it, the urge goes down. That's what's really interesting about how the brain responds. The part of the brain that adds value and is tied to the decision-making system also gets input from the cognitive system."

The problem, Sinha said, is that people often don't wait it out. "We react to it."

Resisting urges is harder for some people than others. A published in the International Journal of Obesity in 2019 found men with obesity had to work harder to exert cognitive control over cravings when presented with food stimuli than men without obesity. Other studies have found men and women experience different types of cravings, with men typically craving savory foods, such as meat, and women craving sweeter foods, such as chocolate.

Reducing exposures to food stimuli can help, Butryn said.

"Modify the parts of your food environment that you can, so you have less exposure to and less access to highly tempting foods that are not a healthy part of the diet," she said. "The less exposure you have to them and the harder you have to work to get these foods, all of that over time will reduce cravings."

That can be accomplished by not buying those foods to begin with, Butryn said. "Most calories are consumed at home," she said. "If you don't have access at home to the foods you crave most, you don't have to use as much willpower to resist them."